| blob | 1fb0466fa6d7dd70889fa23225b614081292d874 |
1 #
2 # For a description of the syntax of this configuration file,
3 # see extra/config/Kconfig-language.txt
4 #
6 mainmenu "uClibc-ng $VERSION C Library Configuration"
8 config DESIRED_TARGET_ARCH
9 string
10 option env="ARCH"
12 config VERSION
13 string
14 option env="VERSION"
16 choice
17 prompt "Target Architecture"
18 default TARGET_aarch64 if DESIRED_TARGET_ARCH = "aarch64"
19 default TARGET_alpha if DESIRED_TARGET_ARCH = "alpha"
20 default TARGET_arc if DESIRED_TARGET_ARCH = "arc"
21 default TARGET_arm if DESIRED_TARGET_ARCH = "arm"
22 default TARGET_avr32 if DESIRED_TARGET_ARCH = "avr32"
23 default TARGET_bfin if DESIRED_TARGET_ARCH = "bfin"
24 default TARGET_cris if DESIRED_TARGET_ARCH = "cris"
25 default TARGET_csky if DESIRED_TARGET_ARCH = "csky"
26 default TARGET_frv if DESIRED_TARGET_ARCH = "frv"
27 default TARGET_h8300 if DESIRED_TARGET_ARCH = "h8300"
28 default TARGET_hppa if DESIRED_TARGET_ARCH = "hppa"
29 default TARGET_i386 if DESIRED_TARGET_ARCH = "i386"
30 default TARGET_ia64 if DESIRED_TARGET_ARCH = "ia64"
31 default TARGET_kvx if DESIRED_TARGET_ARCH = "kvx"
32 default TARGET_lm32 if DESIRED_TARGET_ARCH = "lm32"
33 default TARGET_m68k if DESIRED_TARGET_ARCH = "m68k"
34 default TARGET_metag if DESIRED_TARGET_ARCH = "metag"
35 default TARGET_microblaze if DESIRED_TARGET_ARCH = "microblaze"
36 default TARGET_mips if DESIRED_TARGET_ARCH = "mips"
37 default TARGET_nds32 if DESIRED_TARGET_ARCH = "nds32"
38 default TARGET_nios2 if DESIRED_TARGET_ARCH = "nios2"
39 default TARGET_or1k if DESIRED_TARGET_ARCH = "or1k"
40 default TARGET_powerpc if DESIRED_TARGET_ARCH = "powerpc"
41 default TARGET_riscv64 if DESIRED_TARGET_ARCH = "riscv64"
42 default TARGET_riscv32 if DESIRED_TARGET_ARCH = "riscv32"
43 default TARGET_sh if DESIRED_TARGET_ARCH = "sh"
44 default TARGET_sparc if DESIRED_TARGET_ARCH = "sparc"
45 default TARGET_sparc64 if DESIRED_TARGET_ARCH = "sparc64"
46 default TARGET_tile if DESIRED_TARGET_ARCH = "tile"
47 default TARGET_x86_64 if DESIRED_TARGET_ARCH = "x86_64"
48 default TARGET_xtensa if DESIRED_TARGET_ARCH = "xtensa"
49 help
50 The architecture of your target.
52 config TARGET_aarch64
53 bool "aarch64"
55 config TARGET_alpha
56 bool "alpha"
58 config TARGET_arc
59 bool "arc"
61 config TARGET_arm
62 bool "arm"
64 config TARGET_avr32
65 bool "avr32"
67 config TARGET_bfin
68 bool "bfin"
70 # someone could sync this tree:
71 # http://linux-c6x.org/git/?p=uClibc.git;a=summary
72 config TARGET_c6x
73 bool "c6x"
75 config TARGET_cris
76 bool "cris"
78 config TARGET_csky
79 bool "csky"
81 config TARGET_frv
82 bool "frv"
84 config TARGET_h8300
85 bool "h8300"
87 config TARGET_hppa
88 bool "hppa"
90 config TARGET_i386
91 bool "i386"
93 config TARGET_ia64
94 bool "ia64"
96 config TARGET_kvx
97 bool "kvx"
99 config TARGET_lm32
100 bool "lm32"
102 config TARGET_m68k
103 bool "m68k"
105 config TARGET_metag
106 bool "metag"
108 config TARGET_microblaze
109 bool "microblaze"
111 config TARGET_mips
112 bool "mips"
114 config TARGET_nds32
115 bool "nds32"
117 config TARGET_nios2
118 bool "nios2"
120 config TARGET_or1k
121 bool "or1k"
123 config TARGET_powerpc
124 bool "powerpc"
126 config TARGET_riscv64
127 bool "riscv64"
129 config TARGET_riscv32
130 bool "riscv32"
132 config TARGET_sh
133 bool "superh"
135 config TARGET_sparc
136 bool "sparc"
138 config TARGET_sparc64
139 bool "sparc64"
141 config TARGET_tile
142 bool "tile"
144 config TARGET_x86_64
145 bool "x86_64"
147 config TARGET_xtensa
148 bool "xtensa"
150 endchoice
152 config TARGET_LDSO_NAME
153 string
154 default "ld64-uClibc" if TARGET_ia64
155 default "ld64-uClibc" if TARGET_powerpc64
156 default "ld64-uClibc" if TARGET_sparc64
157 default "ld64-uClibc" if TARGET_x86_64
158 default "ld64-uClibc" if TARGET_kvx
159 default "ld64-uClibc" if CONFIG_MIPS_N64_ABI
160 default "ld-uClibc"
162 config TARGET_ARCH_BITS
163 int
164 default 64 if TARGET_aarch64
165 default 64 if TARGET_ia64
166 default 64 if TARGET_powerpc64
167 default 64 if TARGET_sparc64
168 default 64 if TARGET_x86_64
169 default 64 if TARGET_kvx
170 default 64 if CONFIG_MIPS_N64_ABI
171 default 32
173 menu "Target Architecture Features and Options"
175 if TARGET_aarch64
176 source "extra/Configs/Config.aarch64"
177 endif
179 if TARGET_alpha
180 source "extra/Configs/Config.alpha"
181 endif
183 if TARGET_arm
184 source "extra/Configs/Config.arm"
185 endif
187 if TARGET_avr32
188 source "extra/Configs/Config.avr32"
189 endif
191 if TARGET_bfin
192 source "extra/Configs/Config.bfin"
193 endif
195 if TARGET_cris
196 source "extra/Configs/Config.cris"
197 endif
199 if TARGET_csky
200 source "extra/Configs/Config.csky"
201 endif
203 if TARGET_frv
204 source "extra/Configs/Config.frv"
205 endif
207 if TARGET_h8300
208 source "extra/Configs/Config.h8300"
209 endif
211 if TARGET_hppa
212 source "extra/Configs/Config.hppa"
213 endif
215 if TARGET_i386
216 source "extra/Configs/Config.i386"
217 endif
219 if TARGET_ia64
220 source "extra/Configs/Config.ia64"
221 endif
223 if TARGET_kvx
224 source "extra/Configs/Config.kvx"
225 endif
227 if TARGET_lm32
228 source "extra/Configs/Config.lm32"
229 endif
231 if TARGET_m68k
232 source "extra/Configs/Config.m68k"
233 endif
235 if TARGET_metag
236 source "extra/Configs/Config.metag"
237 endif
239 if TARGET_nds32
240 source "extra/Configs/Config.nds32"
241 endif
243 if TARGET_nios2
244 source "extra/Configs/Config.nios2"
245 endif
247 if TARGET_microblaze
248 source "extra/Configs/Config.microblaze"
249 endif
251 if TARGET_mips
252 source "extra/Configs/Config.mips"
253 endif
255 if TARGET_or1k
256 source "extra/Configs/Config.or1k"
257 endif
259 if TARGET_powerpc
260 source "extra/Configs/Config.powerpc"
261 endif
263 if TARGET_riscv64
264 source "extra/Configs/Config.riscv64"
265 endif
267 if TARGET_riscv32
268 source "extra/Configs/Config.riscv32"
269 endif
271 if TARGET_sh
272 source "extra/Configs/Config.sh"
273 endif
275 if TARGET_sparc
276 source "extra/Configs/Config.sparc"
277 endif
279 if TARGET_sparc64
280 source "extra/Configs/Config.sparc64"
281 endif
283 if TARGET_tile
284 source "extra/Configs/Config.tile"
285 endif
287 if TARGET_x86_64
288 source "extra/Configs/Config.x86_64"
289 endif
291 if TARGET_xtensa
292 source "extra/Configs/Config.xtensa"
293 endif
295 if TARGET_c6x
296 source "extra/Configs/Config.c6x"
297 endif
299 if TARGET_arc
300 source "extra/Configs/Config.arc"
301 endif
303 config TARGET_SUBARCH
304 string
305 default "e500" if CONFIG_E500
306 default "classic" if CONFIG_CLASSIC
307 default "sh4" if CONFIG_SH4
308 default "sh4" if CONFIG_SH4A
309 default "" if CONFIG_386
310 default "i486" if CONFIG_486
311 default "i586" if CONFIG_586
312 default "i686" if CONFIG_686
313 default ""
315 source "extra/Configs/Config.in.arch"
317 endmenu
319 menu "General Library Settings"
321 config HAVE_NO_PIC
322 bool
324 config DOPIC
325 bool "Generate only Position Independent Code (PIC)"
326 default y
327 depends on !HAVE_NO_PIC
328 help
329 If you wish to build all of uClibc as PIC objects, then answer Y here.
330 If you are unsure, then you should answer N.
332 config STATIC_PIE
333 bool "Add support for Static Position Independent Executables (PIE)"
334 default n
335 depends on DOPIC && !UCLIBC_FORMAT_FDPIC_ELF && \
336 (TARGET_aarch64 || TARGET_arm || TARGET_i386 || \
337 TARGET_m68k || TARGET_mips || TARGET_powerpc || \
338 TARGET_riscv64 || TARGET_x86_64 || TARGET_xtensa)
340 config ARCH_HAS_NO_SHARED
341 bool
343 config ARCH_HAS_NO_LDSO
344 bool
345 select ARCH_HAS_NO_SHARED
347 config ARCH_HAS_UCONTEXT
348 bool
350 config HAVE_LDSO
351 bool
353 config HAVE_SHARED
354 bool "Enable shared libraries"
355 depends on !ARCH_HAS_NO_SHARED
356 select HAVE_LDSO
357 default y
358 help
359 If you wish to build uClibc with support for shared libraries then
360 answer Y here. If you only want to build uClibc as a static library,
361 then answer N.
363 config FORCE_SHAREABLE_TEXT_SEGMENTS
364 bool "Only load shared libraries which can share their text segment"
365 depends on HAVE_SHARED
366 select DOPIC
367 help
368 If you answer Y here, the uClibc native shared library loader will
369 only load shared libraries, which do not need to modify any
370 non-writable segments. These libraries haven't set the DT_TEXTREL
371 tag in the dynamic section (==> objdump).
372 All your libraries must be compiled with -fPIC or -fpic, and all
373 assembler function must be written as position independent code (PIC).
374 Enabling this option will make uClibc's shared library loader a
375 little bit smaller and guarantee that no memory will be wasted by
376 badly coded shared libraries.
378 config LDSO_LDD_SUPPORT
379 bool "Native 'ldd' support"
380 depends on HAVE_SHARED
381 default y
382 help
383 Enable all the code needed to support traditional ldd,
384 which executes the shared library loader to resolve all dependencies
385 and then provide a list of shared libraries that are required for an
386 application to function. Disabling this option will make uClibc's
387 shared library loader a little bit smaller.
388 Most people will answer Y.
390 config LDSO_CACHE_SUPPORT
391 bool "Enable library loader cache (ld.so.conf)"
392 depends on HAVE_SHARED
393 default y
394 help
395 Enable this to make use of /etc/ld.so.conf, the shared library loader
396 cache configuration file to support for non-standard library paths.
397 After updating this file, it is necessary to run 'ldconfig' to update
398 the /etc/ld.so.cache shared library loader cache file.
400 config LDSO_PRELOAD_ENV_SUPPORT
401 bool "Enable library loader LD_PRELOAD environment"
402 depends on HAVE_SHARED
403 default y
404 help
405 Enable this to make use of LD_PRELOAD environment variable.
406 A whitespace-separated list of additional, user-specified, ELF shared
407 libraries to be loaded before all others. This can be used to
408 selectively override functions in other shared libraries. For
409 set-user-ID/set-group-ID ELF binaries, only libraries in the standard
410 search directories that are also set-user-ID will be loaded.
412 config LDSO_PRELOAD_FILE_SUPPORT
413 bool "Enable library loader preload file (ld.so.preload)"
414 depends on HAVE_SHARED
415 help
416 Enable this to make use of /etc/ld.so.preload. This file contains a
417 whitespace separated list of shared libraries to be loaded before
418 the program.
420 config LDSO_BASE_FILENAME
421 string "Shared library loader naming prefix"
422 depends on HAVE_SHARED && (LDSO_CACHE_SUPPORT || LDSO_PRELOAD_FILE_SUPPORT)
423 default "ld.so"
424 help
425 If you wish to support both uClibc and glibc on the same system, it
426 is necessary to set this to something other than "ld.so" to avoid
427 conflicts with glibc, which also uses "ld.so". This prevents both
428 libraries from using the same /etc/ld.so.* files. If you wish to
429 support both uClibc and glibc on the same system then you should set
430 this to "ld-uClibc.so".
432 Most people will leave this set to the default of "ld.so".
434 WARNING: Changing the default prefix could cause problems with
435 binutils' ld !
437 config LDSO_STANDALONE_SUPPORT
438 bool "Dynamic linker stand-alone mode support"
439 depends on HAVE_SHARED
440 help
441 The dynamic linker can be run either indirectly through running some
442 dynamically linked program or library (in which case no command line
443 options to the dynamic linker can be passed and, in the ELF case, the
444 dynamic linker which is stored in the .interp section of the program
445 is executed) or directly by running:
447 /lib/ld-uClibc.so.* [OPTIONS] [PROGRAM [ARGUMENTS]]
449 Stand-alone execution is a prerequisite for adding prelink
450 capabilities to uClibc dynamic linker, as well useful for testing an
451 updated version of the dynamic linker without breaking the system.
453 config LDSO_PRELINK_SUPPORT
454 bool "Dynamic linker prelink support"
455 depends on HAVE_SHARED
456 select LDSO_STANDALONE_SUPPORT
457 help
458 The dynamic linker can be used in stand-alone mode by the prelink tool
459 for prelinking ELF shared libraries and binaries to speed up startup
460 time. It also is able to load and handle prelinked libraries and
461 binaries at runtime.
463 config ARCH_VDSO_SUPPORT
464 bool
466 config VDSO_SUPPORT
467 bool "Dynamic linker vDSO support"
468 depends on ARCH_VDSO_SUPPORT
469 help
470 Enable this option to support vDSO loading
472 vDSO provides access to some kernel function without a systemcall
473 if provided by the kernel
475 most archs support gettimeofday() and clock_gettime()
477 vDSO loading can be disabled via VDSO_DISABLE environment variable
479 config UCLIBC_STATIC_LDCONFIG
480 bool "Link ldconfig statically"
481 depends on HAVE_SHARED
482 default y
483 help
484 Enable this option to statically link the ldconfig binary.
486 Making ldconfig static can be beneficial if you have a library
487 problem and need to use ldconfig to recover. Sometimes it is
488 preferable to instead keep the size of the system down, in which
489 case you should disable this option.
491 config LDSO_RUNPATH
492 bool "Enable ELF RUNPATH tag support"
493 depends on HAVE_SHARED
494 default y if LDSO_CACHE_SUPPORT
495 help
496 ELF's may have dynamic RPATH/RUNPATH tags. These tags list paths
497 which extend the library search paths. They are really only useful
498 if a package installs libraries in non standard locations and
499 ld.so.conf support is disabled.
501 Usage of RUNPATH tags is not too common, so disabling this feature
502 should be safe for most people.
504 config LDSO_RUNPATH_OF_EXECUTABLE
505 bool "Use executables RUNPATH/RPATH when searching for libraries."
506 depends on LDSO_RUNPATH
507 default n
508 help
509 Use the executables RUNPATH/RPATH to find to find libraries even
510 though this behavour is not standard. Setting this option causes
511 the uclibc dynamic linker behavour to match the glibc dynamic linker.
513 config LDSO_SAFE_RUNPATH
514 bool "Allow only RUNPATH beginning with /"
515 depends on LDSO_RUNPATH
516 default y
517 help
518 Allow only absolute path in RPATH/RUNPATH.
520 config LDSO_SEARCH_INTERP_PATH
521 bool "Add ldso path to lib search path"
522 depends on HAVE_SHARED
523 default y
524 help
525 The ldso is told where it is being executed from and can use that
526 path to find related core libraries. This is useful by default,
527 but can be annoying in a mixed development environment.
529 i.e. if the ldso is run from /foo/boo/ldso.so, it will start its
530 library search with /foo/boo/
532 If unsure, simply say Y here.
534 config LDSO_LD_LIBRARY_PATH
535 bool "Add LD_LIBRARY_PATH to lib search path"
536 depends on HAVE_SHARED
537 default y
538 help
539 On hardened system it could be useful to disable the use of
540 LD_LIBRARY_PATH environment variable (a colon-separated list of
541 directories in which to search for ELF libraries at execution-time).
543 If unsure, simply say Y here.
545 config UCLIBC_CTOR_DTOR
546 bool
547 default y if !TARGET_riscv64 && !TARGET_lm32
548 help
549 If you wish to build uClibc with support for global constructor
550 (ctor) and global destructor (dtor) support, then answer Y here.
551 When ctor/dtor support is enabled, binaries linked with uClibc must
552 also be linked with crtbegin.o and crtend.o which are provided by gcc
553 (the "*startfile:" and "*endfile:" settings in your gcc specs file
554 may need to be adjusted to include these files). This support will
555 also add a small amount of additional size to each binary compiled vs
556 uClibc. If you will be using uClibc with C++, or if you need the gcc
557 __attribute__((constructor)) and __attribute__((destructor)) to work,
558 then you definitely want to answer Y here. If you don't need ctors
559 or dtors and want your binaries to be as small as possible, then
560 answer N.
562 config LDSO_GNU_HASH_SUPPORT
563 bool "Enable GNU hash style support"
564 depends on HAVE_SHARED && !TARGET_mips
565 help
566 Newest binutils support a new hash style named GNU-hash. The dynamic
567 linker will use the new GNU-hash section (.gnu.hash) for symbol lookup
568 if present into the ELF binaries, otherwise it will use the old SysV
569 hash style (.hash). This ensures that it is completely backward
570 compatible.
571 Further, being the hash table implementation self-contained into each
572 executable and shared libraries, objects with mixed hash style can
573 peacefully coexist in the same process.
575 If you want to use this new feature, answer Y
577 choice
578 prompt "Thread support"
579 default HAS_NO_THREADS
580 help
581 If you want to compile uClibc with pthread support, then answer Y.
582 This will increase the size of uClibc by adding a bunch of locking
583 to critical data structures, and adding extra code to ensure that
584 functions are properly reentrant.
586 config HAS_NO_THREADS
587 bool "none"
588 help
589 Disable thread support.
591 config UCLIBC_HAS_LINUXTHREADS
592 bool "Linuxthreads"
593 # linuxthreads need nanosleep()
594 select UCLIBC_HAS_REALTIME
595 depends on !TARGET_aarch64 && \
596 !TARGET_riscv64 && \
597 !TARGET_riscv32 && \
598 !TARGET_metag
599 help
600 If you want to compile uClibc with Linuxthreads support, then answer Y.
602 config UCLIBC_HAS_THREADS_NATIVE
603 bool "Native POSIX Threading (NPTL)"
604 select UCLIBC_HAS_TLS
605 select UCLIBC_HAS_STDIO_FUTEXES
606 select UCLIBC_HAS_REALTIME
607 # i386 has no lowlevellock support (yet) as opposed to i486 onward
608 depends on !CONFIG_386 && \
609 !TARGET_alpha && \
610 !TARGET_avr32 && \
611 !TARGET_bfin && \
612 !TARGET_c6x && \
613 !TARGET_cris && \
614 !TARGET_frv && \
615 !TARGET_h8300 && \
616 !TARGET_hppa && \
617 !TARGET_ia64 && \
618 (ARCH_USE_MMU || TARGET_arm)
619 help
620 If you want to compile uClibc with NPTL support, then answer Y.
622 endchoice
624 config UCLIBC_HAS_THREADS
625 def_bool y if !HAS_NO_THREADS
627 config UCLIBC_HAS_TLS
628 bool "Thread-Local Storage"
629 depends on UCLIBC_HAS_THREADS_NATIVE
630 help
631 If you want to enable TLS support then answer Y.
632 This is fast an efficient way to store per-thread local data
633 which is not on stack. It needs __thread support enabled in
634 gcc.
636 config PTHREADS_DEBUG_SUPPORT
637 bool "Build pthreads debugging support"
638 depends on UCLIBC_HAS_THREADS
639 help
640 Say Y here if you wish to be able to debug applications that use
641 uClibc's pthreads library. By enabling this option, a library
642 named libthread_db will be built. This library will be dlopen()'d
643 by gdb and will allow gdb to debug the threads in your application.
645 IMPORTANT NOTE! Because gdb must dlopen() the libthread_db library,
646 you must compile gdb with uClibc in order for pthread debugging to
647 work properly.
649 If you are doing development and want to debug applications using
650 uClibc's pthread library, answer Y. Otherwise, answer N.
652 config PTHREADS_STACK_DEFAULT_SIZE
653 int "Default thread stack size"
654 default 4194304 if TARGET_alpha # 4 MiB
655 default 4194304 if TARGET_powerpc # 4 MiB
656 default 2097152 # 2 MiB
657 help
658 Set the default thread stack size. This option is useful on MMU-less
659 systems where the stack size is fixed and the default stack size may
660 be excessively large and waste memory.
662 config UCLIBC_HAS_SYSLOG
663 bool "Syslog support"
664 default y
665 depends on UCLIBC_HAS_NETWORK_SUPPORT
666 select UCLIBC_HAS_SOCKET
667 help
668 Support sending messages to the system logger.
669 This requires socket-support.
671 config UCLIBC_HAS_LFS
672 def_bool y
673 help
674 Large file support (always enabled; config symbol retained for
675 feature test to be compatible with uClibc).
676 choice
677 prompt "Malloc Implementation"
678 default MALLOC if ! ARCH_USE_MMU
679 default MALLOC_STANDARD if ARCH_USE_MMU
681 config MALLOC
682 bool "malloc"
683 help
684 "malloc" use mmap for all allocations and so works very well on
685 MMU-less systems that do not support the brk() system call. It is
686 pretty smart about reusing already allocated memory, and minimizing
687 memory wastage.
688 This is the default for uClinux MMU-less systems.
690 config MALLOC_SIMPLE
691 bool "malloc-simple"
692 help
693 "malloc-simple" is trivially simple and slow as molasses. It
694 was written from scratch for uClibc, and is the simplest possible
695 (and therefore smallest) malloc implementation.
697 This uses only the mmap() system call to allocate and free memory,
698 and does not use the brk() system call at all, making it a fine
699 choice for MMU-less systems with very limited memory. It's 100%
700 standards compliant, thread safe, very small, and releases freed
701 memory back to the OS immediately rather than keeping it in the
702 process's heap for reallocation. It is also VERY SLOW.
704 config MALLOC_STANDARD
705 bool "malloc-standard"
706 depends on ARCH_USE_MMU
707 help
708 "malloc-standard" is derived from the public domain dlmalloc
709 implementation by Doug Lea. It is quite fast, and is pretty smart
710 about reusing already allocated memory, and minimizing memory
711 wastage. This uses brk() for small allocations, while using mmap()
712 for larger allocations. This is the default malloc implementation
713 for uClibc.
715 If unsure, answer "malloc-standard".
717 endchoice
719 config UCLIBC_DYNAMIC_ATEXIT
720 bool "Dynamic atexit() Support"
721 default y
722 help
723 When this option is enabled, uClibc will support an infinite number,
724 of atexit() and on_exit() functions, limited only by your available
725 memory. This can be important when uClibc is used with C++, since
726 global destructors are implemented via atexit(), and it is quite
727 possible to exceed the default number when this option is disabled.
728 Enabling this option adds a few bytes, and more significantly makes
729 atexit and on_exit depend on malloc, which can be bad when compiling
730 static executables.
732 Unless you use uClibc with C++, you should probably answer N.
734 config UCLIBC_HAS_UTMPX
735 bool "utmpx based support for tracking login/logouts to/from the system"
736 help
737 Answer y to enable support for accessing user accounting database.
738 It can be used to track all login/logout to the system.
740 config UCLIBC_HAS_UTMP
741 bool "utmp support (XPG2 compat, SVr4 compat)"
742 depends on UCLIBC_HAS_UTMPX
743 help
744 Answer y to enable legacy SVID support for accessing
745 user accounting database:
746 getutent(), getutid(), getutline(), pututline(),
747 setutent(), endutent(), utmpname() in utmp.h
748 It can be used to track all login/logout to the system.
750 If unsure, answer N and use corresponding POSIX functions
751 from utmpx.h
753 config UCLIBC_SUSV2_LEGACY
754 bool "Enable SuSv2 LEGACY functions"
755 help
756 Enable this option if you want to have SuSv2 LEGACY functions
757 Currently applies to:
759 valloc
761 WARNING! ABI incompatibility.
763 config UCLIBC_SUSV3_LEGACY
764 bool "Enable SuSv3 LEGACY functions"
765 #vfork,
766 # h_errno
767 # gethostbyaddr
768 # gethostbyname
769 help
770 Enable this option if you want to have SuSv3 LEGACY functions
771 in the library, else they are replaced by SuSv3 proposed macros.
772 Currently applies to:
774 bcmp, bcopy, bzero, index, rindex, ftime,
775 bsd_signal, (ecvt), (fcvt), gcvt, (getcontext),
776 (getwd), (makecontext),
777 mktemp, (pthread_attr_getstackaddr), (pthread_attr_setstackaddr),
778 scalb, (setcontext), (swapcontext), ualarm, usleep,
779 wcswcs.
781 WARNING! ABI incompatibility.
783 config UCLIBC_HAS_CONTEXT_FUNCS
784 bool "Use obsolescent context control functions"
785 depends on UCLIBC_SUSV3_LEGACY && ARCH_HAS_UCONTEXT
786 help
787 Add into library the SuSv3 obsolescent functions used for context
788 control. The setcontext family allows the implementation in C of
789 advanced control flow patterns such as iterators, fibers, and
790 coroutines. They may be viewed as an advanced version of
791 setjmp/longjmp; whereas the latter allows only a single non-local jump
792 up the stack, setcontext allows the creation of multiple cooperative
793 threads of control, each with its own stack.
794 These functions are: setcontext, getcontext, makecontext, swapcontext.
796 config UCLIBC_SUSV3_LEGACY_MACROS
797 bool "Enable SuSv3 LEGACY macros"
798 help
799 Enable this option if you want to have SuSv3 LEGACY macros.
800 Currently applies to bcopy/bzero/bcmp/index/rindex et al.
801 WARNING! ABI incompatibility.
803 config UCLIBC_SUSV4_LEGACY
804 bool "Enable SuSv4 LEGACY or obsolescent functions"
805 help
806 Enable this option if you want to have SuSv4 LEGACY functions
807 and macros in the library.
808 Currently applies to:
810 - XSI functions:
811 _longjmp, _setjmp, _tolower, _toupper, ftw, getitimer,
812 gettimeofday, isascii, pthread_getconcurrency,
813 pthread_setconcurrency, setitimer, setpgrp, sighold,
814 sigignore, sigpause, sigrelse, sigset, siginterrupt,
815 tempnam, toascii, ulimit.
817 - Base functions:
818 asctime, asctime_r, ctime, ctime_r, gets, rand_r,
819 tmpnam, utime.
821 WARNING! ABI incompatibility.
823 config UCLIBC_STRICT_HEADERS
824 bool "Hide structures and constants for unsupported features"
825 help
826 Hide structures and constants in headers that should not be used,
827 because the respective feature is disabled.
829 WARNING! enabling this option requires to patch many faulty apps,
830 since they make (wrongly) use of these structures/constants,
831 although the feature was disabled.
833 config UCLIBC_HAS_STUBS
834 bool "Provide stubs for unavailable functionality"
835 help
836 With this option uClibc provides non-functional stubs for
837 functions which are impossible to implement on the target
838 architecture. Otherwise, such functions are simply omitted.
840 config UCLIBC_HAS_SHADOW
841 bool "Shadow Password Support"
842 default y
843 help
844 Answer N if you do not need shadow password support.
845 Most people will answer Y.
847 config UCLIBC_HAS_PROGRAM_INVOCATION_NAME
848 bool "Support for program_invocation_name"
849 help
850 Support for the GNU-specific program_invocation_name and
851 program_invocation_short_name strings. Some GNU packages
852 (like tar and coreutils) utilize these for extra useful
853 output, but in general are not required.
855 At startup, these external strings are automatically set
856 up based on the value of ARGV[0].
858 If unsure, just answer N.
860 config UCLIBC_HAS___PROGNAME
861 bool "Support for __progname"
862 default y
863 help
864 Some packages (like openssh) like to peek into internal libc
865 symbols to make their output a bit more user friendly.
867 At startup, __progname is automatically set up based on the
868 value of ARGV[0].
870 If unsure, just answer N.
872 config UCLIBC_HAS_PTY
873 bool "Support for pseudo-terminals"
874 default y
875 help
876 This enables support for pseudo-terminals (see man 4 pts
877 and man 7 pty).
879 If unsure, just answer Y.
881 config ASSUME_DEVPTS
882 bool "Assume that /dev/pts is a devpts or devfs file system"
883 default y
884 depends on UCLIBC_HAS_PTY
885 help
886 Enable this if /dev/pts is on a devpts or devfs filesystem. Both
887 these filesystems automatically manage permissions on the /dev/pts
888 devices. You may need to mount your devpts or devfs filesystem on
889 /dev/pts for this to work.
891 Most people should answer Y.
893 config UNIX98PTY_ONLY
894 bool "Support only Unix 98 PTYs"
895 default y
896 depends on UCLIBC_HAS_PTY
897 help
898 If you want to support only Unix 98 PTYs enable this. Some older
899 applications may need this disabled and will thus use legacy BSD
900 style PTY handling which is more complex and also bigger than
901 Unix 98 PTY handling.
903 For most current programs, you can generally answer Y.
905 if UNIX98PTY_ONLY
906 config UCLIBC_HAS_GETPT
907 bool "Support getpt() (glibc-compat)"
908 depends on UCLIBC_HAS_PTY
909 help
910 Some packages may need getpt().
911 All of those are non-standard and can be considered
912 GNU/libc compatibility.
913 Either use posix_openpt() or just open /dev/ptmx yourself.
915 If unsure, just say N.
916 endif
918 if !UNIX98PTY_ONLY
919 # Have to use __libc_ptyname{1,2}[] and related bloat
920 config UCLIBC_HAS_GETPT
921 def_bool y
922 endif
924 config UCLIBC_HAS_LIBUTIL
925 bool "Provide libutil library and functions"
926 depends on UCLIBC_HAS_PTY
927 help
928 Provide a libutil library.
929 This non-standard conforming library provides the following
930 utility functions:
932 forkpty(): combines openpty(), fork(2), and login_tty() to
933 create a new process operating in a pseudo-terminal.
934 login(): write utmp and wtmp entries
935 login_tty(): prepares for a login on the tty fd by creating a
936 new session, making fd the controlling terminal for
937 the calling process, setting fd to be the standard
938 input, output, and error streams of the current
939 process, and closing fd.
940 logout(): write utmp and wtmp entries
941 logwtmp(): constructs a utmp structure and calls updwtmp() to
942 append the structure to the utmp file.
943 openpty(): finds an available pseudo-terminal and returns
944 file descriptors for the master and slave
946 This library adds about 3k-4k to your system.
948 config UCLIBC_HAS_TM_EXTENSIONS
949 bool "Support 'struct tm' timezone extension fields"
950 default y
951 help
952 Enabling this option adds fields to 'struct tm' in time.h for
953 tracking the number of seconds east of UTC, and an abbreviation for
954 the current timezone. These fields are not specified by the SuSv3
955 standard, but they are commonly used in both GNU and BSD application
956 code.
958 To strictly follow the SuSv3 standard, leave this disabled.
959 Most people will probably want to answer Y.
961 config UCLIBC_HAS_TZ_CACHING
962 bool "Enable caching of the last valid timezone 'TZ' string"
963 default y
964 help
965 Answer Y to enable caching of the last valid 'TZ' string describing
966 the timezone setting. This allows a quick string compare to avoid
967 repeated parsing of unchanged 'TZ' strings when tzset() is called.
969 Most people will answer Y.
971 config UCLIBC_HAS_TZ_FILE
972 bool "Enable '/etc/TZ' file support to set a default timezone (uClibc-specific)"
973 default y
974 help
975 Answer Y to enable the setting of a default timezone for uClibc.
977 Ordinarily, uClibc gets the timezone information exclusively from the
978 'TZ' environment variable. In particular, there is no support for
979 the zoneinfo directory tree or the /etc/timezone file used by glibc.
981 With this option enabled, uClibc will use the value stored in the
982 file '/etc/TZ' (default path) to obtain timezone information if the
983 'TZ' environment variable is missing or has an invalid value. The
984 file consists of a single line (newline required) of text describing
985 the timezone in the format specified for the TZ environment variable.
987 Doing 'echo CST6CDT > /etc/TZ' is enough to create a valid file.
988 See
989 http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap08.html
990 for details on valid settings of 'TZ'.
992 Most people will answer Y.
994 config UCLIBC_HAS_TZ_FILE_READ_MANY
995 bool "Repeatedly read the '/etc/TZ' file"
996 depends on UCLIBC_HAS_TZ_FILE
997 default y
998 help
999 Answer Y to enable repeated reading of the '/etc/TZ' file even after
1000 a valid value has been read. This incurs the overhead of an
1001 open/read/close for each tzset() call (explicit or implied). However,
1002 setting this will allow applications to update their timezone
1003 information if the contents of the file change.
1005 Most people will answer Y.
1007 config UCLIBC_TZ_FILE_PATH
1008 string "Path to the 'TZ' file for setting the global timezone"
1009 depends on UCLIBC_HAS_TZ_FILE
1010 default "/etc/TZ"
1011 help
1012 This is the path to the 'TZ' file.
1014 Most people will use the default of '/etc/TZ'.
1016 config UCLIBC_FALLBACK_TO_ETC_LOCALTIME
1017 bool "Use /etc/localtime as a fallback"
1018 depends on UCLIBC_HAS_TZ_FILE
1019 default y
1020 help
1021 Answer Y to try to use /etc/localtime file.
1022 On glibc systems this file (if it is in TZif2 format)
1023 contains timezone string at the end.
1025 Most people will answer Y.
1027 config UCLIBC_USE_TIME64
1028 bool "Use *time64 syscalls instead of 32bit ones (if possible)"
1029 depends on TARGET_arc || \
1030 TARGET_arm || \
1031 TARGET_microblaze || \
1032 (TARGET_mips && !CONFIG_MIPS_N64_ABI) || \
1033 TARGET_or1k || \
1034 TARGET_powerpc || \
1035 TARGET_riscv32 || \
1036 TARGET_sparc || \
1037 TARGET_sh || \
1038 TARGET_xtensa
1039 # TODO: add support for other architectures
1040 default n
1042 help
1043 Replace 32bit syscalls to their 64/time64 analog if possible.
1045 endmenu
1047 menu "Advanced Library Settings"
1049 config UCLIBC_PWD_BUFFER_SIZE
1050 int "Buffer size for getpwnam() and friends"
1051 default 256
1052 range 12 1024
1053 help
1054 This sets the value of the buffer size for getpwnam() and friends.
1055 By default, this is 256. (For reference, glibc uses 1024).
1056 The value can be found using sysconf() with the _SC_GETPW_R_SIZE_MAX
1057 parameter.
1059 config UCLIBC_GRP_BUFFER_SIZE
1060 int "Buffer size for getgrnam() and friends"
1061 default 256
1062 range 12 1024
1063 help
1064 This sets the value of the buffer size for getgrnam() and friends.
1065 By default, this is 256. (For reference, glibc uses 1024).
1066 The value can be found using sysconf() with the _SC_GETGR_R_SIZE_MAX
1067 parameter.
1069 comment "Support various families of functions"
1071 config UCLIBC_LINUX_SPECIFIC
1072 bool "Linux specific functions"
1073 default y
1074 help
1075 accept4(), bdflush(),
1076 capget(), capset(), eventfd(), fallocate(),
1077 fstatfs(), getrandom(), inotify_*(), ioperm(), iopl(),
1078 madvise(), modify_ldt(), pipe2(), personality(),
1079 prctl()/arch_prctl(), pivot_root(), modify_ldt(),
1080 ppoll(), readahead(), reboot(), remap_file_pages(),
1081 sched_getaffinity(), sched_setaffinity(), sendfile(),
1082 setfsgid(), setfsuid(), setresgid(), setresuid(),
1083 splice(), vmsplice(), tee(), signalfd(), statfs(),
1084 swapoff(), swapon(), sync_file_range(), syncfs(),
1085 _sysctl(), sysinfo(), timerfd_*(), vhangup(), umount(),
1086 umount2()
1088 config UCLIBC_HAS_GNU_ERROR
1089 bool "Support GNU extensions for error-reporting"
1090 default y
1091 help
1092 Support for the GNU-specific error(), error_at_line(),
1093 void (* error_print_progname)(), error_message_count
1094 functions and variables. Some GNU packages
1095 utilize these for extra useful output, but in general
1096 are not required.
1098 If unsure, just answer N.
1100 config UCLIBC_BSD_SPECIFIC
1101 bool "BSD specific functions"
1102 default y
1103 help
1104 mincore(), getdomainname(), setdomainname()
1106 If unsure, say N.
1108 config UCLIBC_HAS_BSD_ERR
1109 bool "BSD err functions"
1110 default y
1111 help
1112 These functions are non-standard BSD extensions.
1113 err(), errx(), warn(), warnx(), verr(), verrx(), vwarn(), vwarnx()
1115 If unsure, say N.
1117 config UCLIBC_HAS_OBSOLETE_BSD_SIGNAL
1118 bool "BSD obsolete signal functions"
1119 help
1120 These functions are provided as a compatibility interface for
1121 programs that make use of the historical System V signal API.
1122 This API is obsolete:
1123 new applications should use the POSIX signal API (sigaction(2),
1124 sigprocmask(2), etc.).
1125 Affected functions:
1127 sigset(), sighold(), sigrelse(), sigignore()
1129 If unsure, say N.
1131 config UCLIBC_HAS_BSD_B64_NTOP_B64_PTON
1132 bool "Support b64_ntop(), b64_pton() (bsd-compat)"
1133 help
1134 Answer Y if you need additional BSD compatibility
1135 (e.g. for openbsd-netcat).
1137 Most people will say N.
1139 config UCLIBC_HAS_OBSOLETE_SYSV_SIGNAL
1140 bool "SYSV obsolete signal functions"
1141 help
1142 Use of sysv_signal() should be avoided; use sigaction(2) instead.
1144 If unsure, say N.
1146 config UCLIBC_NTP_LEGACY
1147 bool "ntp_*() aliases"
1148 help
1149 Provide legacy aliases for ntp functions:
1150 ntp_adjtime(), ntp_gettime()
1152 It is safe to say N here.
1154 config UCLIBC_SV4_DEPRECATED
1155 bool "Enable SVr4 deprecated functions"
1156 help
1157 These functions are DEPRECATED in System V release 4.
1158 Say N unless you desparately need one of the functions below:
1160 ustat() [use statfs(2) in your code instead]
1162 config UCLIBC_HAS_REALTIME
1163 bool "Realtime-related family of SUSv functions"
1164 default y
1165 help
1166 These functions are part of the Timers option and need not
1167 be available on all implementations.
1168 Includes AIO, message-queue, scheduler, semaphore functions:
1170 aio.h
1171 mqueue.h
1172 sched.h
1173 semaphore.h
1175 aio_cancel()
1176 aio_error()
1177 aio_fsync()
1178 aio_read()
1179 lio_listio()
1180 aio_return()
1181 aio_suspend()
1182 aio_write()
1183 clock_getres(), clock_gettime(), clock_settime()
1184 fdatasync()
1185 mlockall(), munlockall()
1186 mlock(), munlock()
1187 mq_close()
1188 mq_getattr()
1189 mq_notify()
1190 mq_open()
1191 mq_receive()
1192 mq_send()
1193 mq_setattr()
1194 mq_unlink()
1195 nanosleep()
1196 sched_getparam()
1197 sched_get_priority_max(), sched_get_priority_min()
1198 sched_getscheduler()
1199 sched_rr_get_interval()
1200 sched_setparam()
1201 sched_setscheduler()
1202 sem_close()
1203 sem_destroy()
1204 sem_getvalue()
1205 sem_init()
1206 sem_open()
1207 sem_post()
1208 sem_trywait(), sem_wait()
1209 sem_unlink()
1210 sigqueue()
1211 sigtimedwait(), sigwaitinfo()
1212 timer_create()
1213 timer_delete()
1214 timer_getoverrun(), timer_gettime(), timer_settime()
1216 config UCLIBC_HAS_ADVANCED_REALTIME
1217 bool "Advanced realtime-related family of SUSv functions"
1218 default y
1219 depends on UCLIBC_HAS_REALTIME
1220 help
1221 These functions are part of the Timers option and need not
1222 be available on all implementations.
1224 clock_getcpuclockid()
1225 clock_nanosleep()
1226 mq_timedreceive()
1227 mq_timedsend()
1228 posix_fadvise()
1229 posix_fallocate()
1230 posix_madvise()
1231 posix_memalign()
1232 posix_mem_offset()
1233 posix_spawnattr_destroy(), posix_spawnattr_init()
1234 posix_spawnattr_getflags(), posix_spawnattr_setflags()
1235 posix_spawnattr_getpgroup(), posix_spawnattr_setpgroup()
1236 posix_spawnattr_getschedparam(), posix_spawnattr_setschedparam()
1237 posix_spawnattr_getschedpolicy(), posix_spawnattr_setschedpolicy()
1238 posix_spawnattr_getsigdefault(), posix_spawnattr_setsigdefault()
1239 posix_spawnattr_getsigmask(), posix_spawnattr_setsigmask()
1240 posix_spawn_file_actions_addclose()
1241 posix_spawn_file_actions_adddup2()
1242 posix_spawn_file_actions_addopen()
1243 posix_spawn_file_actions_destroy()
1244 posix_spawn_file_actions_init()
1245 posix_spawn()
1246 posix_spawnp()
1247 posix_typed_mem_get_info()
1248 pthread_mutex_timedlock()
1249 sem_timedwait()
1251 #config UCLIBC_HAS_TERMIOS
1252 # bool "termios functions"
1253 # default y
1254 # help
1255 # Get and set terminal attributes, line control, get and set baud
1256 # rate.
1257 # termios(), tcgetattr(), tcsetattr(), tcsendbreak(), tcdrain(),
1258 # tcflush(), tcflow(), cfmakeraw(), cfgetospeed(), cfgetispeed(),
1259 # cfsetispeed(), cfsetospeed(), cfsetspeed()
1260 #
1261 # If unsure, say Y.
1263 config UCLIBC_HAS_EPOLL
1264 bool "epoll"
1265 default y
1266 help
1267 epoll_create(), epoll_ctl(), epoll_wait() functions.
1269 config UCLIBC_HAS_XATTR
1270 bool "Extended Attributes"
1271 default y
1272 help
1273 Extended Attributes support.
1275 setxattr()
1276 lsetxattr()
1277 fsetxattr()
1278 getxattr()
1279 lgetxattr()
1280 fgetxattr()
1281 listxattr()
1282 llistxattr()
1283 flistxattr()
1284 removexattr()
1285 lremovexattr()
1286 fremovexattr()
1288 Say N unless you need support for extended attributes and the
1289 filesystems do actually support them.
1291 config UCLIBC_HAS_PROFILING
1292 bool "Profiling support"
1293 default y
1294 help
1295 gcc's -finstrument-functions needs these.
1297 Most people can safely answer N.
1299 config UCLIBC_HAS_CRYPT_IMPL
1300 bool "libcrypt support"
1301 default y
1302 help
1303 libcrypt contains crypt(), setkey() and encrypt()
1305 config UCLIBC_HAS_SHA256_CRYPT_IMPL
1306 bool "libcrypt SHA256 support"
1307 depends on UCLIBC_HAS_CRYPT_IMPL
1308 help
1309 This adds support for SHA256 password hashing via the crypt() function.
1310 Say N here if you do not need SHA256 crypt support.
1312 config UCLIBC_HAS_SHA512_CRYPT_IMPL
1313 bool "libcrypt SHA512 support"
1314 depends on UCLIBC_HAS_CRYPT_IMPL
1315 help
1316 This adds support for SHA512 password hashing via the crypt() function.
1317 Say N here if you do not need SHA512 crypt support.
1319 config UCLIBC_HAS_CRYPT_STUB
1320 bool "libcrypt stubs"
1321 default y
1322 depends on !UCLIBC_HAS_CRYPT_IMPL
1323 help
1324 Standards mandate that crypt(3) provides a stub if it is unavailable.
1325 If you enable this option then stubs for
1326 crypt(), setkey() and encrypt()
1327 will be provided in a small libcrypt.
1329 config UCLIBC_HAS_CRYPT
1330 def_bool y
1331 depends on UCLIBC_HAS_CRYPT_IMPL || UCLIBC_HAS_CRYPT_STUB
1332 endmenu
1334 menuconfig UCLIBC_HAS_NETWORK_SUPPORT
1335 bool "Networking Support"
1336 default y
1337 help
1338 Say N here if you do not need network support.
1340 if UCLIBC_HAS_NETWORK_SUPPORT
1341 config UCLIBC_HAS_SOCKET
1342 bool "Socket support"
1343 default y
1344 help
1345 If you want to include support for sockets then answer Y.
1347 config UCLIBC_HAS_IPV4
1348 bool "IP version 4 support"
1349 default y
1350 select UCLIBC_HAS_SOCKET
1351 help
1352 If you want to include support for the Internet Protocol
1353 (IP version 4) then answer Y.
1355 Most people will say Y.
1357 config UCLIBC_HAS_IPV6
1358 bool "IP version 6 support"
1359 select UCLIBC_HAS_SOCKET
1360 help
1361 If you want to include support for the next version of the Internet
1362 Protocol (IP version 6) then answer Y.
1364 Most people should answer N.
1366 config UCLIBC_USE_NETLINK
1367 bool "Use netlink to query interfaces"
1368 depends on UCLIBC_HAS_SOCKET
1369 help
1370 In newer versions of Linux (2.4.17+), support was added for querying
1371 network device information via netlink rather than the old style
1372 ioctl's. Most of the time, the older ioctl style is sufficient (and
1373 it is smaller than netlink), but if you find that not all of your
1374 devices are being returned by the if_nameindex() function, you will
1375 have to use the netlink implementation.
1377 Most people can safely answer N.
1379 config UCLIBC_SUPPORT_AI_ADDRCONFIG
1380 bool "Support the AI_ADDRCONFIG flag"
1381 depends on UCLIBC_USE_NETLINK
1382 help
1383 The implementation of AI_ADDRCONFIG is aligned with the glibc
1384 implementation using netlink to query interfaces to find both
1385 ipv4 and ipv6 support. This is only needed if an application uses
1386 the AI_ADDRCONFIG flag.
1388 Most people can safely answer N.
1390 config UCLIBC_HAS_BSD_RES_CLOSE
1391 bool "Support res_close() (bsd-compat)"
1392 help
1393 Answer Y if you desperately want to support BSD compatibility in
1394 the network code.
1396 Most people will say N.
1398 config UCLIBC_HAS_COMPAT_RES_STATE
1399 bool "Use compatible but bloated _res"
1400 default y
1401 help
1402 Answer Y if you build network utilities and they muck with resolver
1403 internals a lot (_res global structure). uclibc does not use most
1404 of _res.XXX fields, and with this option OFF they won't even exist.
1405 Which will make e.g. dig build fail.
1406 Answering N saves around 400 bytes in bss.
1408 config UCLIBC_HAS_EXTRA_COMPAT_RES_STATE
1409 bool "Use extra compatible but extra bloated _res"
1410 help
1411 Answer Y if selecting UCLIBC_HAS_COMPAT_RES_STATE is not enough.
1412 As far as I can say, this should never be needed.
1414 config UCLIBC_HAS_RESOLVER_SUPPORT
1415 bool "DNS resolver functions"
1416 select UCLIBC_HAS_COMPAT_RES_STATE
1417 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1418 help
1419 Provide implementations for DNS resolver functions.
1420 In particular, the following functions will be added to the
1421 library:
1423 ns_skiprr, ns_initparse, ns_parserr, ns_msg_getflag,
1424 res_mkquery, res_init, res_ninit, res_close, res_nclose
1425 res_query, res_search, res_querydomain,
1426 dn_expand, dn_comp,
1427 ns_name_uncompress, ns_name_ntop, ns_name_pton, ns_name_unpack,
1428 ns_name_pack, ns_name_compress, ns_name_skip, dn_skipname,
1429 ns_get16, ns_get32, ns_put16, ns_put32
1431 choice
1432 prompt "DNS Query ID generation"
1433 default UCLIBC_DNSRAND_MODE_PRNGPLUS
1434 help
1435 Control how successive dns query ids' are generated during
1436 dns lookup.
1438 config UCLIBC_DNSRAND_MODE_URANDOM
1439 bool "urandom"
1440 help
1441 "urandom" uses /dev/urandom available under many unix flavours
1442 to generate dns query id. This can generate good random ids,
1443 by dipping into the entropy pool maintained by the system.
1444 However this is relatively slow compared to the other options,
1445 as it may involve cryptographic operations internally and
1446 kernel-userspace handshake.
1448 config UCLIBC_DNSRAND_MODE_CLOCK
1449 bool "clock"
1450 depends on UCLIBC_HAS_REALTIME
1451 help
1452 "clock" uses CLOCK_REALTIME of the system to generate plausibly
1453 random dns query id. Systems require to have clock source with
1454 nanosec granularity mapped to this clock id for this to generate
1455 plausibly random values. However has processor and io performances
1456 improve in future, its effectiveness can get impacted.
1458 config UCLIBC_DNSRAND_MODE_PRNGPLUS
1459 bool "prngplus"
1460 help
1461 "prngplus" uses random prng available within uclibc, to indirectly
1462 generate the dns query id. This tries to provide a good balance
1463 between speed and randomness to an extent. It periodically reseeds
1464 the prng using random value generated from either the urandom or
1465 else the clock, if either of them is available. Additionally applies
1466 transform (one way, if possible) on internal generated random values.
1467 These make it difficult to infer internal state of prng from unbroken
1468 sequences of exposed random values.
1469 This is the default.
1471 config UCLIBC_DNSRAND_MODE_SIMPLECOUNTER
1472 bool "simplecounter"
1473 help
1474 "simplecounter" uses a simple counter to generate dns query id.
1475 This is a very simple logic and can be subjected to dns poison
1476 attack relatively easily.
1477 It is recommended to avoid this option.
1479 endchoice
1482 endif
1485 menu "String and Stdio Support"
1487 config UCLIBC_HAS_STRING_GENERIC_OPT
1488 bool "Use faster (but larger) generic string functions"
1489 default y
1490 help
1491 Answer Y to use the (tweaked) glibc generic string functions.
1493 In general, they are faster (but 3-5K larger) than the base
1494 uClibc string functions which are optimized solely for size.
1496 Many people will answer Y.
1498 config UCLIBC_HAS_STRING_ARCH_OPT
1499 bool "Use arch-specific assembly string functions (where available)"
1500 default y
1501 help
1502 Answer Y to use any archtecture-specific assembly language string
1503 functions available for this target plaform.
1505 Note that assembly implementations are not available for all string
1506 functions, so some generic (written in C) string functions may
1507 still be used.
1509 These are small and fast, the only reason _not_ to say Y here is
1510 for debugging purposes.
1512 config UCLIBC_HAS_STDIO_FUTEXES
1513 bool "Use futexes for multithreaded I/O locking"
1514 depends on UCLIBC_HAS_THREADS_NATIVE
1515 help
1516 If you want to compile uClibc to use futexes for low-level
1517 I/O locking, answer Y. Otherwise, answer N.
1519 config UCLIBC_HAS_CTYPE_TABLES
1520 bool "Use Table Versions Of 'ctype.h' Functions."
1521 default y
1522 help
1523 Answer Y to use table versions of the 'ctype.h' functions.
1524 While the non-table versions are often smaller when building
1525 statically linked apps, they work only in stub locale mode.
1527 Most people will answer Y.
1529 config UCLIBC_HAS_CTYPE_SIGNED
1530 bool "Support Signed Characters In 'ctype.h' Functions."
1531 depends on UCLIBC_HAS_CTYPE_TABLES
1532 default y
1533 help
1534 Answer Y to enable support for passing signed char values to
1535 the 'ctype.h' functions. ANSI/ISO C99 and SUSv3 specify that
1536 these functions are only defined for unsigned char values and
1537 EOF. However, glibc allows negative signed char values as well
1538 in order to support 'broken old programs'.
1540 Most people will answer Y.
1542 choice
1543 prompt "ctype argument checking"
1544 depends on UCLIBC_HAS_CTYPE_TABLES
1545 default UCLIBC_HAS_CTYPE_UNSAFE
1546 help
1547 Please select the invalid arg behavior you want for the 'ctype'
1548 functions.
1550 The 'ctype' functions are now implemented using table lookups, with
1551 the arg being the index. This can result in incorrect memory accesses
1552 or even segfaults for args outside of the allowed range.
1554 NOTE: This only affects the 'ctype' _functions_. It does not affect
1555 the macro implementations.
1557 config UCLIBC_HAS_CTYPE_UNSAFE
1558 bool "Do not check -- unsafe"
1560 config UCLIBC_HAS_CTYPE_CHECKED
1561 bool "Detect and handle appropriately"
1563 config UCLIBC_HAS_CTYPE_ENFORCED
1564 bool "Issue a diagnostic and abort()"
1566 endchoice
1569 config UCLIBC_HAS_WCHAR
1570 bool "Wide Character Support"
1571 help
1572 Answer Y to enable wide character support. This will make uClibc
1573 much larger. It is also currently required for locale support.
1575 Most people will answer N.
1577 config UCLIBC_HAS_LIBICONV
1578 bool "Iconv Support"
1579 select UCLIBC_HAS_WCHAR
1580 help
1581 Add tiny iconv support for charset conversion from and to UTF-8.
1583 config UCLIBC_HAS_LIBINTL
1584 bool "Intl stubs support"
1585 help
1586 If you enable this option you get stubs for the gettext family of
1587 functions.
1589 config UCLIBC_HAS_LOCALE
1590 bool "Locale Support"
1591 select UCLIBC_HAS_WCHAR
1592 select UCLIBC_HAS_CTYPE_TABLES
1593 select UCLIBC_HAS_LIBICONV
1594 help
1595 uClibc now has full ANSI/ISO C99 locale support (except for
1596 wcsftime() and collating items in regex). Be aware that enabling
1597 this option will make uClibc much larger.
1599 Enabling UCLIBC_HAS_LOCALE with the default set of supported locales
1600 (169 UTF-8 locales, and 144 locales for other codesets) will enlarge
1601 uClibc by around 300k. You can reduce this size by building your own
1602 custom set of locate data (see extra/locale/LOCALES for details).
1604 uClibc's locale support is still under development. For example,
1605 codesets using shift states are not currently supported. Support is
1606 planned in the next iteration of locale support.
1608 Answer Y to enable locale support. Most people will answer N.
1610 choice
1612 prompt "Locale data"
1613 depends on UCLIBC_HAS_LOCALE
1614 default UCLIBC_BUILD_MINIMAL_LOCALE
1616 config UCLIBC_BUILD_MINIMAL_LOCALE
1617 bool "Only selected locales"
1618 depends on UCLIBC_HAS_LOCALE
1619 help
1620 If you do not need all locales that are available on your
1621 host-box, then set this to 'Y'.
1623 config UCLIBC_BUILD_ALL_LOCALE
1624 bool "All locales"
1625 depends on UCLIBC_HAS_LOCALE
1626 help
1627 This builds all the locales that are available on your
1628 host-box.
1630 endchoice
1632 config UCLIBC_BUILD_MINIMAL_LOCALES
1633 string "locales to use"
1634 depends on UCLIBC_BUILD_MINIMAL_LOCALE
1635 default "en_US"
1636 help
1637 Space separated list of locales to use.
1639 E.g.:
1640 en_US en_GB de_AT
1641 default:
1642 en_US
1644 config UCLIBC_HAS_XLOCALE
1645 bool "Extended Locale Support (experimental/incomplete)"
1646 depends on UCLIBC_HAS_LOCALE
1647 help
1648 Answer Y to enable extended locale support similar to that provided
1649 by glibc. This is primarily intended to support libstd++
1650 functionality.
1651 However, it also allows thread-specific locale selection via
1652 uselocale().
1654 Most people will answer N.
1656 config UCLIBC_HAS_HEXADECIMAL_FLOATS
1657 bool "Support hexadecimal float notation"
1658 depends on UCLIBC_HAS_CTYPE_TABLES
1659 depends on UCLIBC_HAS_FLOATS
1660 help
1661 Answer Y to enable support for hexadecimal float notation in the
1662 (wchar and) char string to floating point conversion functions, as
1663 well as support for the %a and %A conversion specifiers in the
1664 *printf() and *scanf() functions.
1666 Most people will answer N.
1668 config UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1669 bool "Support glibc's \"'\" flag for allowing locale-specific digit grouping"
1670 depends on UCLIBC_HAS_LOCALE
1671 depends on UCLIBC_HAS_FLOATS
1672 help
1673 Answer Y to enable support for glibc's \"'\" flag for allowing
1674 locale-specific digit grouping in base 10 integer conversions and
1675 appropriate floating point conversions in the *printf() and *scanf()
1676 functions.
1678 Most people will answer N.
1680 config UCLIBC_HAS_SCANF_LENIENT_DIGIT_GROUPING
1681 bool "Do not require digit grouping when the \"'\" flag is specified"
1682 depends on UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1683 default y
1684 help
1685 Answer Y to make digit grouping optional when the \"'\" flag is
1686 specified.
1687 This is the standard glibc behavior. If the initial string of digits
1688 exceeds the maximum group number, the input will be treated as a
1689 normal non-grouped number.
1691 Most people will answer N.
1693 config UCLIBC_HAS_GLIBC_CUSTOM_PRINTF
1694 bool "Support glibc's register_printf_function() (glibc-compat)"
1695 depends on !USE_OLD_VFPRINTF
1696 help
1697 Answer Y to support glibc's register_printf_function() to allow an
1698 application to add its own printf conversion specifiers.
1699 parse_printf_format() is also enabled.
1701 NOTE: Limits the number or registered specifiers to 10.
1702 NOTE: Requires new conversion specifiers to be ASCII
1703 characters (0-0x7f). This is to avoid problems with processing
1704 format strings in locales with different multibyte conversions.
1706 Most people will answer N.
1708 config USE_OLD_VFPRINTF
1709 bool "Use the old vfprintf implementation"
1710 depends on !UCLIBC_HAS_WCHAR
1711 help
1712 Set to true to use the old vfprintf instead of the new. This is
1713 roughly C89 compliant with some extensions, and is much smaller.
1714 However, it does not support wide chars, positional args, or glibc
1715 custom printf specifiers.
1717 Most people will answer N.
1719 config UCLIBC_PRINTF_SCANF_POSITIONAL_ARGS
1720 int "Maximum number of positional args. Either 0 or >= 9."
1721 depends on !USE_OLD_VFPRINTF
1722 default 9
1723 help
1724 Set the maximum number of positional args supported by the
1725 printf/scanf functions. The Single Unix Specification Version 3
1726 requires a minimum value of 9. Setting this to a value lower than
1727 9 will disable positional arg support and cause the NL_ARGMAX macro
1728 in limits.h to be #undef'd.
1730 WARNING! The workspace to support positional args is currently
1731 allocated on the stack. You probably don't want to set
1732 this to too high a value.
1734 Most people will answer 9.
1736 choice
1737 prompt "Stdio buffer size"
1738 default UCLIBC_HAS_STDIO_BUFSIZ_4096
1739 help
1740 Please select a value for BUFSIZ. This will be used by the
1741 stdio subsystem as the default buffer size for a file, and
1742 affects fopen(), setvbuf(), etc.
1744 NOTE: Setting this to 'none' will disable buffering completely.
1745 However, BUFSIZ will still be defined in stdio.h as 256 because
1746 many applications use this value.
1748 config UCLIBC_HAS_STDIO_BUFSIZ_NONE
1749 bool "none (WARNING - BUFSIZ will be 256 in stdio.h)"
1750 depends on !UCLIBC_HAS_WCHAR
1752 config UCLIBC_HAS_STDIO_BUFSIZ_256
1753 bool "256 (minimum ANSI/ISO C99 value)"
1755 config UCLIBC_HAS_STDIO_BUFSIZ_512
1756 bool "512"
1758 config UCLIBC_HAS_STDIO_BUFSIZ_1024
1759 bool "1024"
1761 config UCLIBC_HAS_STDIO_BUFSIZ_2048
1762 bool "2048"
1764 config UCLIBC_HAS_STDIO_BUFSIZ_4096
1765 bool "4096"
1767 config UCLIBC_HAS_STDIO_BUFSIZ_8192
1768 bool "8192"
1770 # If you add more choices, you will need to update uClibc_stdio.h.
1772 endchoice
1774 choice
1775 prompt "Stdio builtin buffer size (uClibc-specific)"
1776 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1777 default UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1778 help
1779 When a FILE is created with fopen(), an attempt is made to allocate
1780 a BUFSIZ buffer for it. If the allocation fails, fopen() will still
1781 succeed but the FILE will be unbuffered.
1783 This option adds a small amount of space to each FILE to act as an
1784 emergency buffer in the event of a buffer allocation failure.
1786 Most people will answer None.
1788 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1789 bool "None"
1791 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_4
1792 bool "4"
1794 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_8
1795 bool "8"
1797 # If you add more choices, you will need to update uClibc_stdio.h.
1799 endchoice
1801 config UCLIBC_HAS_STDIO_SHUTDOWN_ON_ABORT
1802 bool "Attempt to shutdown stdio subsystem when abort() is called."
1803 help
1804 ANSI/ISO C99 requires abort() to be asyn-signal-safe. So there was
1805 a behavioral change made in SUSv3. Previously, abort() was required
1806 to have the affect of fclose() on all open streams. The wording has
1807 been changed to "may" from "shall".
1809 Most people will answer N.
1811 config UCLIBC_HAS_STDIO_GETC_MACRO
1812 bool "Provide a macro version of getc()"
1813 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1814 default y
1815 help
1816 Provide a macro version of getc().
1818 Most people will answer Y.
1820 config UCLIBC_HAS_STDIO_PUTC_MACRO
1821 bool "Provide a macro version of putc()"
1822 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1823 default y
1824 help
1825 Provide a macro version of putc().
1827 Most people will answer Y.
1829 config UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION
1830 bool "Support auto-r/w transition"
1831 default y
1832 help
1833 Answer Y to enable the stdio subsystem to automaticly transition
1834 between reading and writing. This relaxes the ANSI/ISO C99
1835 requirement:
1837 When a file is opened with update mode ('+' as the second or third
1838 character in the list of mode argument values), both input and output
1839 may be performed on the associated stream. However, output shall not
1840 be directly followed by input without an intervening call to the
1841 fflush function or to a file positioning function (fseek, fsetpos,
1842 or rewind), and input shall not be directly followed by output without
1843 an intervening call to a file positioning function, unless the input
1844 operation encounters endÂofÂfile.
1846 Most people will answer Y.
1848 config UCLIBC_HAS_FOPEN_LARGEFILE_MODE
1849 bool "Support an fopen() 'F' flag for large file mode (uClibc-specific)"
1850 help
1851 Answer Y to enable a uClibc-specific extension to allow passing an
1852 additional 'F' flag in the mode string for fopen() to specify that
1853 the file should be open()ed with the O_LARGEFILE flag set.
1855 Most people will answer N.
1857 config UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE
1858 bool "Support an fopen() 'x' flag for exclusive mode (glibc-compat)"
1859 help
1860 Answer Y to support a glibc extension to allow passing
1861 additional 'x' flag in the mode string for fopen() to specify that
1862 the file should be open()ed with the O_EXCL flag set.
1864 Most people will answer N.
1866 config UCLIBC_HAS_FOPEN_CLOSEEXEC_MODE
1867 bool "Support an fopen() 'e' flag for close-on-exec mode (glibc-compat)"
1868 help
1869 Answer Y to support a glibc extension to allow passing
1870 additional 'e' flag in the mode string for fopen() to specify that
1871 the file should be open()ed with the O_CLOEXEC flag set.
1873 Most people will answer N.
1875 config UCLIBC_HAS_GLIBC_CUSTOM_STREAMS
1876 bool "Support fmemopen(), open_memstream(), and fopencookie() (glibc-compat)"
1877 help
1878 Answer Y to support the glibc 'custom stream' extension functions
1879 fmemopen(), open_memstream(), and fopencookie().
1881 NOTE: There are some minor differences regarding seeking behavior.
1883 Most people will answer N.
1885 config UCLIBC_HAS_PRINTF_M_SPEC
1886 bool "Support the '%m' specifier in printf format strings (glibc-compat)"
1887 help
1888 Answer Y to support a glibc extension to interpret '%m' in printf
1889 format strings as an instruction to output the error message string
1890 (as generated by strerror) corresponding to the current value of
1891 'errno'.
1893 Most people will answer N.
1895 config UCLIBC_HAS_ERRNO_MESSAGES
1896 bool "Include the errno message text in the library"
1897 default y
1898 help
1899 Answer Y if you want to include the errno message text in the
1900 library. This adds about 3K to the library, but enables strerror()
1901 to generate text other than 'Unknown error <number>'.
1903 Most people will answer Y.
1905 config UCLIBC_HAS_SYS_ERRLIST
1906 bool "Support sys_errlist[] (obsolete-compat)"
1907 depends on UCLIBC_HAS_ERRNO_MESSAGES
1908 help
1909 Answer Y if you want to support the obsolete sys_errlist[].
1910 This adds about 0.5k to the library, except for the mips
1911 arch where it adds over 4K.
1913 WARNING! In the future, support for sys_errlist[] may be unavailable
1914 in at least some configurations. In fact, it may be removed
1915 altogether.
1917 Most people will answer N.
1919 Application writers: use the strerror(3) function.
1921 config UCLIBC_HAS_SIGNUM_MESSAGES
1922 bool "Include the signum message text in the library"
1923 default y
1924 help
1925 Answer Y if you want to include the signum message text in the
1926 library. This adds about 0.5K to the library, but enables strsignal()
1927 to generate text other than 'Unknown signal <number>'.
1929 Most people will answer Y.
1931 config UCLIBC_HAS_SYS_SIGLIST
1932 bool "Support sys_siglist[] (bsd-compat)"
1933 depends on UCLIBC_HAS_SIGNUM_MESSAGES
1934 help
1935 Answer Y if you want to support sys_siglist[].
1937 WARNING! In the future, support for sys_siglist[] may be unavailable
1938 in at least some configurations. In fact, it may be removed
1939 altogether.
1941 Most people will answer N.
1943 config UCLIBC_HAS_GNU_GETOPT
1944 bool "Support gnu getopt"
1945 default y
1946 help
1947 Answer Y if you want to include full gnu getopt() instead of a
1948 (much smaller) SUSv3 compatible getopt().
1949 Note that getopt_long, getopt_long_only as well as getsubopt
1950 are implemented on top of this choice.
1952 Most people will answer Y.
1954 config UCLIBC_HAS_GETOPT_LONG
1955 bool "Support getopt_long/getopt_long_only (glibc-compat)"
1956 default y
1957 help
1958 Answer Y if you want to include getopt_long[_only()] used by many
1959 apps.
1961 Most people will answer Y.
1963 config UCLIBC_HAS_GNU_GETSUBOPT
1964 bool "Support getsubopt"
1965 default y
1966 help
1967 Answer Y if you want to include getsubopt().
1969 Most people will answer Y.
1971 config UCLIBC_HAS_ARGP
1972 bool "Support argp"
1973 select UCLIBC_HAS_GETOPT_LONG
1974 select UCLIBC_HAS_GNU_GETOPT
1975 select UCLIBC_HAS_WCHAR
1976 default n
1977 help
1978 Argp is an interface for parsing unix-style argument vectors. Unlike
1979 the common getopt interface, it provides many advanced features in
1980 addition to parsing options, such as automatic output in response to
1981 `--help' and `--version' options.
1982 A library can export an argp option parser, which programs can easily
1983 use in conjunction with their own option parser.
1984 Argp support is needed by elfutils libdw.
1986 Most people can safely answer N.
1988 endmenu
1991 menu "Big and Tall"
1993 config UCLIBC_HAS_REGEX
1994 bool "Regular Expression Support"
1995 default y
1996 help
1997 POSIX regular expression code is really big -- 53k all by itself.
1998 If you don't use regular expressions, turn this off and save space.
1999 Of course, if you only statically link, leave this on, since it will
2000 only be included in your apps if you use regular expressions.
2002 config UCLIBC_HAS_FNMATCH
2003 bool "fnmatch Support"
2004 default y
2005 help
2006 POSIX fnmatch.
2008 config UCLIBC_HAS_WORDEXP
2009 bool "Support the wordexp() interface"
2010 depends on UCLIBC_HAS_GLOB
2011 help
2012 The SuSv3 wordexp() interface performs word expansions per the Shell
2013 and Utilities volume of IEEE Std 1003.1-2001, Section 2.6. It is
2014 intended for use by applications that want to implement all of the
2015 standard Bourne shell expansions on input data.
2017 This interface is rarely used, and very large. Unless you have a
2018 pressing need for wordexp(), you should probably answer N.
2020 config UCLIBC_HAS_NFTW
2021 bool "Support the nftw() interface"
2022 help
2023 The SuSv3 nftw() interface is used to recursively descend
2024 directory paths while repeatedly calling a function.
2026 This interface is rarely used, and adds around 4.5k. Unless you have
2027 a pressing need for nftw(), you should probably answer N.
2029 config UCLIBC_HAS_FTW
2030 bool "Support the ftw() interface (SUSv4-obsolete)"
2031 depends on UCLIBC_SUSV4_LEGACY
2032 help
2033 The SuSv3 ftw() interface is used to recursively descend
2034 directory paths while repeatedly calling a function.
2036 This interface is rarely used, and adds around 4.5k. Unless you have
2037 a pressing need for ftw(), you should probably answer N.
2039 config UCLIBC_HAS_FTS
2040 bool "Support the fts() interface (bsd-compat)"
2041 help
2042 The fts functions are provided for traversing UNIX file hierarchies.
2044 This interface is currently used by the elfutils and adds
2045 around 7.5k.
2046 You should port your application to use the POSIX nftw()
2047 interface.
2049 Unless you need to build/use elfutils, you should prolly answer N.
2051 config UCLIBC_HAS_GLOB
2052 bool "Support the glob() interface"
2053 depends on UCLIBC_HAS_FNMATCH
2054 default y
2055 help
2057 The glob interface is somewhat large (weighing in at about 2,5k). It
2058 is used fairly often, but is an option since people wanting to go for
2059 absolute minimum size may wish to omit it.
2061 Most people will answer Y.
2063 config UCLIBC_HAS_GNU_GLOB
2064 bool "Support gnu glob() interface"
2065 depends on UCLIBC_HAS_GLOB
2066 help
2067 The gnu glob interface is somewhat larger (weighing in at about 4,2k)
2068 than it's SuSv3 counterpart (and is out of date). It is an old copy
2069 from glibc and does not support all the GNU specific options.
2071 Answer Y if you want to include full gnu glob() instead of the smaller
2072 SUSv3 compatible glob().
2074 Most people will answer N.
2076 endmenu
2081 menu "Library Installation Options"
2083 config RUNTIME_PREFIX
2084 string "uClibc runtime library directory"
2085 default "/usr/$(TARGET_ARCH)-linux-uclibc/"
2086 help
2087 RUNTIME_PREFIX is the directory into which the uClibc runtime
2088 libraries will be installed. The result will look something
2089 like the following:
2090 $(RUNTIME_PREFIX)/
2091 lib/ <contains all runtime libraries>
2092 usr/bin/ldd <the ldd utility program>
2093 sbin/ldconfig <the ldconfig utility program>
2094 This value is used by the 'make install' Makefile target. Since this
2095 directory is compiled into the shared library loader, you will need to
2096 recompile uClibc if you change this value...
2098 For a typical target system this should be set to "/", such that
2099 'make install' will install /lib/libuClibc-<VERSION>.so
2101 config DEVEL_PREFIX
2102 string "uClibc development environment directory"
2103 default "/usr/$(TARGET_ARCH)-linux-uclibc/usr/"
2104 help
2105 DEVEL_PREFIX is the directory into which the uClibc development
2106 environment will be installed. The result will look something
2107 like the following:
2108 $(DEVEL_PREFIX)/
2109 lib/ <contains static libs>
2110 include/ <Where all the header files go>
2111 This value is used by the 'make install' Makefile target when
2112 installing a uClibc development environment.
2114 For a typical target system this should be set to "/usr", such that
2115 'make install' will install /usr/include/<header files>.
2117 config MULTILIB_DIR
2118 string "library path component"
2119 default "lib"
2120 help
2121 Path component where libraries reside.
2123 For a typical target system this should be set to "lib", such that
2124 'make install' will install libraries to "/lib" and "/usr/lib"
2125 respectively
2126 DEVEL_PREFIX/MULTILIB_DIR
2127 RUNTIME_PREFIX/MULTILIB_DIR
2129 Other settings may include "lib32" or "lib64".
2131 config HARDWIRED_ABSPATH
2132 bool "Hardwire absolute paths into linker scripts"
2133 default y
2134 help
2135 This prepends absolute paths to the libraries mentioned in linker
2136 scripts such as libc.so.
2138 This is a build time optimization. It has no impact on dynamic
2139 linking at runtime, which doesn't use linker scripts.
2141 You must disable this to use uClibc with old non-sysroot toolchains,
2142 such as the prebuilt binary cross compilers at:
2143 http://uclibc.org/downloads/binaries
2145 The amount of time saved by this optimization is actually too small to
2146 measure. The linker just had to search the library path to find the
2147 linker script, so the dentries are cache hot if it has to search the
2148 same path again. But it's what glibc does, so we do it too.
2150 endmenu
2153 menu "Security options"
2155 config UCLIBC_BUILD_PIE
2156 bool "Build utilities as ET_DYN/PIE executables"
2157 depends on HAVE_SHARED
2158 depends on TARGET_arm || TARGET_frv || TARGET_i386 || TARGET_mips || TARGET_powerpc || TARGET_nds32
2159 select FORCE_SHAREABLE_TEXT_SEGMENTS
2160 help
2161 If you answer Y here, ldd and iconv are built as ET_DYN/PIE
2162 executables.
2164 It requires gcc-3.4 and binutils-2.15 (for arm 2.16) or later.
2165 More about ET_DYN/PIE binaries on <http://pax.grsecurity.net/> .
2167 WARNING: This option also enables FORCE_SHAREABLE_TEXT_SEGMENTS, so
2168 all libraries have to be built with -fPIC or -fpic, and all
2169 assembler functions must be written as position independent
2170 code (PIC).
2172 config HAVE_NO_SSP
2173 bool
2175 config UCLIBC_HAS_SSP
2176 bool "Support for GCC stack smashing protector"
2177 depends on !HAVE_NO_SSP
2178 help
2179 Add code to support GCC's -fstack-protector[-all] option to uClibc.
2180 This requires GCC 4.1 or newer. GCC does not have to provide libssp,
2181 the needed functions are added to ldso/libc instead.
2183 GCC's stack protector is a reimplementation of IBM's propolice.
2184 See http://www.trl.ibm.com/projects/security/ssp/ and
2185 http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt
2186 for details.
2188 Note that NOEXECSTACK on a kernel with address space randomization
2189 is generally sufficient to prevent most buffer overflow exploits
2190 without increasing code size. This option essentially adds debugging
2191 code to catch them.
2193 Most people will answer N.
2195 config SSP_QUICK_CANARY
2196 bool "Use simple guard values without accessing /dev/urandom"
2197 depends on UCLIBC_HAS_SSP
2198 help
2199 Use gettimeofday(2) to define the __guard without accessing
2200 /dev/urandom.
2201 WARNING: This makes smashing stack protector vulnerable to timing
2202 attacks.
2203 Most people will answer N.
2205 choice
2206 prompt "Propolice protection blocking signal"
2207 depends on UCLIBC_HAS_SSP
2208 depends on DODEBUG
2209 default PROPOLICE_BLOCK_SEGV
2210 help
2211 "abort" use SIGABRT to block offending programs.
2212 This is the default implementation.
2214 "segfault" use SIGSEGV to block offending programs.
2215 Use this for debugging.
2217 If unsure, answer "abort".
2219 config PROPOLICE_BLOCK_ABRT
2220 bool "abort"
2222 config PROPOLICE_BLOCK_SEGV
2223 bool "segfault"
2225 endchoice
2227 config UCLIBC_BUILD_SSP
2228 bool "Build uClibc with -fstack-protector"
2229 depends on UCLIBC_HAS_SSP
2230 help
2231 Build all uClibc libraries and executables with -fstack-protector,
2232 adding extra stack overflow checking to most uClibc functions.
2234 config UCLIBC_BUILD_RELRO
2235 bool "Build uClibc with linker option -z RELRO"
2236 depends on HAVE_SHARED
2237 default y
2238 help
2239 Build all libraries and executables with "ld -z relro".
2241 This tells the linker to mark chunks of an executable or shared
2242 library read-only after applying dynamic relocations. (This comes
2243 up when a global const variable is initialized to the address of a
2244 function or the value of another global variable.)
2246 This is a fairly obscure option the ld man page doesn't even bother
2247 to document properly. It's a security paranoia issue that's more
2248 likely to consume memory (by allocating an extra page) rather than
2249 save it.
2251 This is explained in more depth at
2252 http://www.airs.com/blog/archives/189
2254 Nobody is likely to care whether you say Y or N here.
2256 config UCLIBC_BUILD_NOW
2257 bool "Build uClibc with linker option -z NOW"
2258 depends on HAVE_SHARED
2259 help
2260 Build all libraries and executables with "ld -z now".
2262 This tells the linker to resolve all symbols when the library is
2263 first loaded, rather than when each function is first called. This
2264 increases start-up latency by a few microseconds and may do
2265 unnecessary work (resolving symbols that are never used), but the
2266 realtime people like it for making microbenchmark timings slightly
2267 more predictable and in some cases it can be slightly faster due to
2268 CPU cache behavior (not having to fault the linker back in to do
2269 lazy symbol resolution).
2271 Most people can't tell the difference between selecting Y or N here.
2273 config UCLIBC_BUILD_NOEXECSTACK
2274 bool "Build uClibc with noexecstack marking"
2275 default y
2276 help
2277 Mark all assembler files as noexecstack, which will mark uClibc
2278 as not requiring an executable stack. (This doesn't prevent other
2279 files you link against from claiming to need an executable stack, it
2280 just won't cause uClibc to request it unnecessarily.)
2282 This is a security thing to make buffer overflows harder to exploit.
2283 By itself, it's kind of useless, as Linus Torvalds explained in 1998:
2284 http://old.lwn.net/1998/0806/a/linus-noexec.html
2286 It only actually provides any security when combined with address
2287 space randomization, explained here: http://lwn.net/Articles/121845/
2289 Address space randomization is on by default in current linux
2290 kernels (although it can be disabled using the option
2291 CONFIG_COMPAT_BRK).
2293 You should probably say Y.
2295 endmenu
2297 menu "Development/debugging options"
2299 config CROSS_COMPILER_PREFIX
2300 string "Cross-compiling toolchain prefix"
2301 default ""
2302 help
2303 The prefix used to execute your cross-compiling toolchain. For
2304 example, if you run 'arm-linux-uclibc-gcc' to compile something,
2305 then enter 'arm-linux-uclibc-' here.
2307 config UCLIBC_EXTRA_CFLAGS
2308 string "Extra CFLAGS"
2309 default ""
2310 help
2311 Add any additional CFLAGS to be used to build uClibc.
2313 config DODEBUG
2314 bool "Enable debugging symbols"
2315 select EXTRA_WARNINGS
2316 help
2317 Say Y here if you wish to compile uClibc with debugging symbols.
2318 This will allow you to use a debugger to examine uClibc internals
2319 while applications are running. This increases the size of the
2320 library considerably and should only be used when doing development.
2321 If you are doing development and want to debug uClibc, answer Y.
2323 Otherwise, answer N.
2325 config DODEBUG_PT
2326 bool "Build pthread with debugging output"
2327 depends on UCLIBC_HAS_THREADS && UCLIBC_HAS_LINUXTHREADS
2328 help
2329 Enable debug output in libpthread. This is only useful when doing
2330 development in libpthread itself.
2332 Otherwise, answer N.
2334 config DOSTRIP
2335 bool "Strip libraries and executables"
2336 default y
2337 depends on !DODEBUG
2338 help
2339 Say Y here if you do wish to strip all uClibc libraries and
2340 executables. No stripping increases the size of the binaries
2341 considerably, but makes it possible to debug uClibc libraries.
2342 Most people will answer Y.
2344 config DOASSERTS
2345 bool "Build with run-time assertion testing"
2346 help
2347 Say Y here to include runtime assertion tests.
2348 This enables runtime assertion testing in some code, which can
2349 increase the size of the library and incur runtime overhead.
2350 If you say N, then this testing will be disabled.
2352 config SUPPORT_LD_DEBUG
2353 bool "Build the shared library loader with debugging support"
2354 depends on HAVE_SHARED
2355 help
2356 Answer Y here to enable all the extra code needed to debug the uClibc
2357 native shared library loader. The level of debugging noise that is
2358 generated depends on the LD_DEBUG environment variable... Just set
2359 LD_DEBUG to something like: 'LD_DEBUG=token1,token2,.. prog' to
2360 debug your application. Diagnostic messages will then be printed to
2361 the stderr.
2363 For now these debugging tokens are available:
2364 detail provide more information for some options
2365 move display copy processing
2366 symbols display symbol table processing
2367 reloc display relocation processing; detail shows the
2368 relocation patch
2369 nofixups never fixes up jump relocations
2370 bindings displays the resolve processing (function calls);
2371 detail shows the relocation patch
2372 vdso display vdso symbol table processing
2373 all Enable everything!
2375 The additional environment variable:
2376 LD_DEBUG_OUTPUT=file
2377 redirects the diagnostics to an output file created using
2378 the specified name and the process id as a suffix.
2380 An excellent start is simply:
2381 $ LD_DEBUG=binding,move,symbols,reloc,detail ./appname
2382 or to log everything to a file named 'logfile', try this
2383 $ LD_DEBUG=all LD_DEBUG_OUTPUT=logfile ./appname
2385 If you are doing development and want to debug uClibc's shared library
2386 loader, answer Y. Mere mortals answer N.
2388 config SUPPORT_LD_DEBUG_EARLY
2389 bool "Build the shared library loader with early debugging support"
2390 depends on HAVE_SHARED
2391 help
2392 Answer Y here to if you find the uClibc shared library loader is
2393 crashing or otherwise not working very early on. This is typical
2394 only when starting a new port when you haven't figured out how to
2395 properly get the values for argc, argv, environ, etc. This method
2396 allows a degree of visibility into the very early shared library
2397 loader initialization process. If you are doing development and want
2398 to debug the uClibc shared library loader early initialization,
2399 answer Y. Mere mortals answer N.
2401 config UCLIBC_MALLOC_DEBUGGING
2402 bool "Build malloc with debugging support"
2403 depends on MALLOC || MALLOC_STANDARD
2404 select DOASSERTS
2405 help
2406 Answer Y here to compile extra debugging support code into malloc.
2407 Malloc debugging output may then be enabled at runtime using the
2408 MALLOC_DEBUG environment variable.
2410 The value of MALLOC_DEBUG should be an integer, which is interpreted
2411 as a bitmask with the following bits:
2412 1 - do extra consistency checking
2413 2 - output messages for malloc/free calls and OS
2414 allocation calls
2415 4 - output messages for the `MMB' layer
2416 8 - output messages for internal malloc heap manipulation
2417 calls
2419 Because this increases the size of malloc appreciably (due to strings
2420 etc), you should say N unless you need to debug a malloc problem.
2422 config UCLIBC_HAS_BACKTRACE
2423 bool "Add support for application self-debugging"
2424 depends on HAVE_SHARED
2425 help
2426 Answer Y here to compile support for application self-debugging that
2427 provides the following new functions:
2428 backtrace, backtrace_symbols, backtrace_symbols_fd
2430 The backtrace functionality is currently supported on some platforms, and it
2431 based on dwarf2 informations to properly work, so any application that
2432 want to use backtrace needs to be built with -fexceptions flag.
2434 The symbol names may be unavailable without the use of special linker
2435 options. For systems using the GNU linker, it is necessary to use the
2436 -rdynamic linker option too. Note that names of "static" functions are not
2437 exposed, and won't be available in the backtrace.
2439 config WARNINGS
2440 string "Compiler Warnings"
2441 default "-Wall"
2442 help
2443 Set this to the set of compiler warnings you wish to see while compiling.
2445 config EXTRA_WARNINGS
2446 bool "Enable extra annoying warnings"
2447 help
2448 If you wish to build with extra warnings enabled, say Y here.
2450 endmenu